Apparatus for constructing potential gradient

ABSTRACT

Apparatus constructing the potential gradient of a potential distribution on conductive paper or the like as measured by a plurality of linearly arranged probes. The probes are scanned so as to selectively apply the voltage between different probes to one input of an X-Y recorder while a synchronized voltage indicating the position of the probes being scanned is applied to another input of the X-Y recorder.

llnfited States atent n91 Kobayashi et al.

[451 Sept. 25, 1973 APPARATUS FOR CONSTRUCTING POTENTIAL GRADIENT [75]Inventors: Takao Kobayashi; Tadahiko Sasaki,

both of Tokyo, Japan [73] Assignee: lwatsu Electric Co., Ltd., Tokyo,

Japan [22] Filed: Aug. 20, 1971 [2]] Appl. No.: 173,427

[52] U.S. Cl. 324/72 [51] Int. Cl GOlr 29/14 [58] Field of Search324/72, 64, 29, 32;

[56] References Cited OTHER PUBLICATIONS Mickelsen, J. K.; GeneralElectric Rev.; November 1949; pgs. 19 to 23. Green, Jr.; Review of Sci.Instrum.; Vol. 19; No. 10; October 1948; pages 646-653.

Primary Examiner-Rudolph V. Rolinec Assistant ExaminerErnest F. KarlsenAttorneyWoodcock, Washburn, Kurtz & Mackiewicz [57] ABSTRACT 5 Claims,14 Drawing Figures I SCANNING I 7 POT. DET I CKT X-Y RECORDER 5CONSTRUCTION MEANS STEPWAVE VOLTAGE GEN CONT CKT PATiNTi-lnsiPzslsmSHEET ll]? 5 FIG.1 1 POT. DET i SCANNNG 7 CKT X-Y RECORDER 5vCONSTRUCTION MEANS STEPWAVE I VOLTAGE GEN CONT CKT FIG. 2 W

a w 15 K u U -11 PATENTfiUssPzslsva SHEET 30F 5 FIG.7

FIG. 8

FIG.9

AIIPARATIJS FOR CONSTRUCTING POTENTIAL GRADIENT FIELD OF THE INVENTIONThis invention relates to an apparatus for constructing a potentialgradient and more particularly to automatically constructing thepotential gradient of a potential distribution.

In order to imitate various phenomena and analyze the phenomena a kindof analysis is utilized for example in which a conductive paper(hereafter termed anacon-paper) that has been turned conductive afterbeing uniformly coated with carbon on a ground paper is used and on thisanacon-paper a desired shape of electrode is provided and on thiselectrode a predetermined voltage is given whereby the potentialdistribution appearing on the anacon-paper is examined.

Hitherto, when one wants to know the potential distribution on theanacon-paper, it was the practice that the operator puts two probeskeeping a proper distance between them on the anacon-paper and readspotential difference detected by the probes on a digital voltmeter andplots the said potential difference on the graph paper. The method oftracing the potential distribution in this way is extremely complicatedand inaccurate.

SUMMARY AND OBJECTS OF THE INVENTION An object of this invention is toprovide an apparatus for automatically constructing a potentialgradient.

Another object of this invention is to provide an apparatus forconstructing a potential gradient in an extremely short time.

Further object of this invention is to provide an apparatus forconstructing a potential gradient extremely accurately.

According to the present invention, apparatus for constructing potentialgradient comprises a potential detector having a plurality of,preferably many, voltage probes, a scanning circuit scanning in orderthe output of said potential detector and applying said output to aconstruction means, a position-responding voltage generator generatingvoltage responding to the position of said voltage probes and applyingsaid voltage to said construction means, and said construction meansconstructing the relation between the potential and distance on anoptional line segment of an object of measurement by the two signalsfrom said scanning circuit and said position-responding voltagegenerator whereby the potential gradient of potential distribution onsaid line segment can be constructed by means of said constructionmeans.

The invention will now be described, by way of example, with referenceto the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram of oneembodiment of an apparatus for constructing potential gradient inaccordance with this invention;

FIG. 2 is a sectional view of one embodiment of mechanism indicatingrelation between an anaconpaper and probes in accordance with thisinvention;

FIG. 3 is a perspective view, partially cut-off, of one embodiment of apotential detector shown in FIG. 1 in accordance with this invention;

FIG. 4 is a plan view, partially cut-off, of the potential detectorshown in FIG. 3;

FIG. 5 is a front view, partially cut-off, of the potential detectorshown in FIGS. 34;

FIG. 6 is a sectional view taken along the line VI VI of FIG. 4;

FIG. 7 is a circuit diagram of one embodiment of a scanning circuitshown in FIG. 1 in accordance with this invention;

FIG. 8 is a circuit diagram of one embodiment of a voltage generatorshown in FIG. 1 in accordance with this invention;

FIG. 9 is an output waveform of the voltage generator shown in FIG. 8;

FIG. 10 shows an example of construction by way of apparatus forconstructing potential gradient shown in FIG. 1;

FIG. 11 is a circuit diagram of one embodiment showing the positions ofelectrodes on anacon-paper and the place of measurement in accordancewith this invention;

FIG. 12 shows a construction of a potential gradient on the line XII XIIof FIG. 11;

FIG. 13 is a circuit diagram of another embodiment of the generatorshown in FIG. 1 in accordance with this invention; and

FIG. 14 is an output waveform of the generator shown in FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 is illustrated anapparatus for constructing potential gradient comprising a potentialdetector 1, a scanning circuit 3, a step-wave voltage generator 5,construction means 7 and a control circuit 9.

In FIGS. 2-6 is shown one embodiment of the potential detector 1. Thepotential detector 1 is provided with a plurality of probes l7 and isformed in a way that the probes l7 lay on an anacon-paper 11 made up bycoating carbon 15 on an insulating ground paper 13. In this embodiment,the probes 17 are made up by nickel silver of 0.45 mm with the end tipssharpened to a diameter of 40 p" In this embodiment, nickel silver isemployed as the probes 17 but phosphor bronz or tungusten is alsosuitable for the material of the probes. The probes l7 fixed on holes 31of an adapter plate 19 made up by delrin (trademark of polyacetal). Theprobes take the form of L and have a horizontal portion 27 of about 42mm and a vertical portion 25 of about 15 mm. On the horizontal portion27 of the probe 17 is a curved portion 29 which is formed to inclineabout 12 degrees against horizontal in a state that the end tip of theprobe does not contact with the anacon-paper l l. The curve portion 29is also formed to get the vertical portion 25 of the probe 17 almostperpendicular against the anacon-paper 11 in a state that the end tip ofthe probe 17 contacts with the anacon-paper 11. The point where thecurve portion 29 is set up is about 13.5 mm away from the hole 31 of theadapter plate 19, namely divides about 1:2 of the horizontal portion 27.

The probe 17 has spring action by which the probe 17 is formed tocontact with the anacon-paper 11 under the contact strength of about 6 7g.

The adapter plate 19 to be fixed with the probes 17 is made up bysynthetic resin and is provided with a plurality of holes 31, v-shapedguide grooves 21 and round guide holes 23 respectively. The guide holesare provided in response to the number of probes 17 and the horizontalportions 25 of the probes 17 are inserted in 7 these guide holes. As thematerial of the adapter plate forming the guide holes 23, teflon(trademark of polyt'luoroethylene) is suitable in consideration ofasmooth horizontal movement of the probe 17. When transparency is sought,polycarbonate is suitable as the material of the adapter plate. In thisembodiment, the diameter of the guide hole 23 is about 0.5 mm and 101numbers of this guide hole are arranged in line with equal distance ofabout lmm. The guide groove 21 is formed to guide the horizontal portion27 of the probe 17 and 101 numbers of this groove corresponding to thenumber of the probe 17 are formed.

The adapter plate 19 with which the probe 17 is fixed tends to riseupward due to repulsive force according to spring action of the probe17. To eliminate this, a weight (not shown) is affixed on the adapterplate 19.

In FIG. 7 is illustrated a scanning circuit 3 which scans the circuit ofplural probes 17 of the potential detector 1 whereby the output of theprobe 17 is selectively applied to the construction means 7 on the nextstep. The scanning circuit 3 is provided with a first scanning meansconsisting of a 100 fixed contacts 33 and a travelling contact 35 thatcontacts with these fixed contacts 33 in order, and a second scanningmeans consisting of 100 fixed contacts 37 and a travelling contact 39that contacts with these fixed contacts in order.

The first fixed contact 33 in the first scanning means is connected withthe first probe 17 of potential detector 1 while the second fixedcontact 33 with the second probe 17 respectively and in this way the100th fixed contact 33 is connected with the 100th probe 17. In thesecond scanning means, the first fixed contact 37 is connected with thesecond probe 17 of said potential detector 1 while the second fixedcontact 37 with the third probe 17 respectively and, in this way, thellst probe 17. And, synchronizing with the scanning of the 1st 100thfixed contacts 33 by the travelling contact 35, the travelling contact39 is made up to scan the 1st 100th fixed contacts 37.

The travelling contacts 35,39 rotate in accordance with signals from thecontrol circuit 9.

The travelling contact 35 is connected with wire 41 while the travellingcontact 39 with wire 42 respectively and the output from these wires 41and 42 is applied to the construction means 7 on the next step. Thoughnone is illustarated in drawings, between the wires 41, 42 and to theconstruction means 7 is connected a low-pass filter circuit consiting ofa resistance and a capacitor. The low-pass filter circuit functions toreduce noises and, at the same time to smooth the motion of pen of theX-Y recorder of the construction means 7. Further, though notillustrated in drawings, the scanning circuit 3 is provided with a probecontact detecting means that detects if the probe 17 surely contacts theanacon-paper 11 or not. This detection is done ahead of construction. Ifthere is any probe that doesn't properly contact an anacon paper 11, analarm will be generated at the control circuit 9 as a detecting signalis applied to the control circuit 9 from the potential detector 1 andthen the apparatus will suspend operation. The scanning circuit 3 inthis embodiment is constituted by the use of a mechanical switch but anelectronic switch is possibly used instead.

In FIG. 8 is shown an example of the stepwave voltage generator which isformed so that the travelling contact 49 slides on the 1st 100th fixedcontacts 47 arranged in order and shaped as semi-circle as a whole.Between the respective fixed contacts 47, resistance 51 corresponding tothe distance of the probes 17 are connected. The stepwave voltagegenerator 5 is provided with a terminal 45 to apply the voltage thereonand wire 53 to take out the voltage from the travelling contact 49respectively. And, the wire 53 is connected with the construction means7 on the next step. The travelling contact 49 of the stepwave voltagegenerator 5 is made to operate in a synchronized manner with thetravelling contacts 35 and 39 of the scanning circuit 3 whereby avoltage 55 provided with a wave form shown in FIG. 9 is generated fromthe stepwave voltage generator 5. The horizontal axis in FIG. 9indicates the distance L between the probes 17 while the vertical axisindicates the voltage V available at the wire 53 respectively. In FIG.9, N N N N Nn represent the positions of the probes 17. The stepwavevoltage generator 5 generates a voltage corresponding to the position ofthe probe 17 and the voltage thus generated is applied to the inputterminal of the X axisof the construction means on the next step. Inthis embodiment, a stepwave voltage is used as the voltage correspondingto the position of each probe 17. However, the voltage 71 of thewaveform shown in FIG. 14 increases linearly with respect to thedistance L of horizontal axis can also be used. The voltage 71 of thewaveform shown in FIG. 14 can be formed by the circuit shown in FIG. 13.The circuit in FIG. 13 generating the voltage corresponding to theposition consists of slide resistance 75 and slider 77. In this circuitwith a reference voltage applied to the slide resistance 75 through theterminal 73, waveform voltage 71 indicated in FIG. 14 can be obtained atthe wire 79.

Particulars of the construction means 7, though not illustrated indrawings, are the X-Y recorder which has hitherto been well known. Inthis'construction means, the voltage from the stepwave voltage generatoris applied to the X axis input terminal while the voltage from thescanning circuit 3 is applied to the Y axis input terminal respectively.

The control circuit 9 comprises two kinds of circuits; one is a circuitwhich applies timing signal to the scanning circuit 3 and to thestepwave voltage generator 5, and the other is a circuit directing avertical movement of pen in the construction means 7. In other words,the control circuit 9 is constituted to apply timing signals to thescanning circuit 3 and the stepwave voltage generator 5, and to rotatethe travelling contacts 35, 39 of the scanning circuit 3 and thetravelling contact 49 of the stepwave voltage generator 5 by thesetiming signals. Furthermore, the control circuit 9 generates controlsignals which enable vertical recording pen movement thereby permittingthe recording pen to contact the recording paper when recording beginsby the construction means and to separate from the recording paper whenrecording suspends.

This control circuit 9 is a circuit for overall control whenconstructing with the X-Y recorder.

Performance of the apparatus for constructing potential gradient havingsuch a constitution as aforementioned is dealt with as follows. First ofall, the potential detector 1 is put on the anacon-paper 11 havingpotential distribution. As the result, the probes 17 are pushed upwardby the anacon-paper 11 and contact with the anacon-paper 11 with contactforce of 6 7 g. Even if there existed unevenness on the surface ofanaconpaper 11, if the unevenness was below about 1 mm, detection ofvoltage by the probes 17 can be done as the respective probes B7 areformed to engage in the vertical motion independently.

Then, the timing signal from the control circuit 9 lets the travellingcontacts 35, 39 of the scanning circuit 3 and the travelling contact 49of the stepwave voltage generator 5 start rotating with synchronization.Then the voltage between the lst and 2nd probes 17 isapplied to theinput terminal of the Y axis of the construction means 7 through thescanning circuit 3. While the voltage from the probes 17 is applied to aY axis input terminal, the voltage equal to one travel step from thestepwave voltage generator 5 is added to the X axis input terminal ofthe construction means 7. In other words, the voltage of the differencebetween the volt; age responding tothe position of the 1st probe and thevoltage responding to the position of the 2nd probe 17 is is applied tothe Y axis input terminal. Then, keeping the voltage applied to theinput terminal of the X axis, the voltage between the 2nd probe 17 andthe 3rd probe 17 is applied to the input terminal of the Y axis of theconstruction means 7 and this sort of operation goes on in order toobtain a construction 57 as shown in FIG. 10 is obtained. FIG. 10 is aconstruction in which the horizontal axis indicates a position ordistance L while the vertical axis indicates voltage V respectively.This construction 57 was made in this way, i.e. at first the Y axis wasconstrugted by the potential difference between the 1st probe 17 and theZnd probe 17, then the X axis was constructed by the voltage respondingto the space or distance between the 1st probe 17 and the 2nd probe 17and this sort of operation was repeated.

Next, an embodiment constructing potential gradient shown in FIGS. 11and 12 will be dealt with. As shown in FIG. 11 four electrodes 59, 61,63 and 65 of conductive paint form a square on the anacon-paper. Theconfronting electrodes are commonly connected respectively, theseelectrodes are connected with the terminal of direct-current powersource and then by applying voltage of about 1 v to the electrodes thepotential distribution was formed on the anacon-paper. By arranging theprobes 17 on the XII-XII line in FIG. 11, the potential gradient wasconstructed as seen in the construction 69 in FIG. 12. This kind ofconstruction can be made by computation & etc, but the operation itselfwas fairly troublesome. According to the apparatus for constructingpotential gradient in accordance with this invention, however, theconstruction 69 as illustrated in FIG. 12 can be done within about oneminute.

Although embodiments of this invention have been described in detailwith reference to the accompanying drawings, it is to be understood thatthe invention is not limited to the details shown and described, andthat various changes and modifications can be made.

What is claimed is:

1. Apparatus for constructing a potential gradient comprising:

a potential detector comprising a plurality of voltage probes havingpredetermined positions;

a scanning circuit comprising switching means connected with each ofsaid voltage probes and means to selectively switch said switching meansso as to obtain the voltage between a selected two of said voltageprobes at the output of said switching means;

a position indicating voltage generator synchronized with said scanningcircuit so as to generate a position indicating voltage corresponding toeach of the selected two of said voltage probes at the output of saidswitching means; and

X-Y construction means comprising recording means capable of moving inthe X axis direction and the Y axis direction in response to X axis andY axis inputs respectively, said output of said scanning circuit beingcoupled to one of said inputs and said output of said positionindicating voltage generator being coupled to the other of said inputsso to record the potential gradient of the potential distribution.

2. The apparatus according to claim 1 wherein said potential detectorcomprises a plurality of voltage probes resiliently contacting a surfacehaving a potential distribution and means for maintaining said voltageprobes in predetermined positions.

3. The apparatus according to claim 1 wherein said scanning circuitcomprises fixed contacts connected with said respective voltage probesand travelling contacts successively engaging said fixed contacts.

4. The apparatus according to claim 1 wherein said position voltagegenerator comprises a stepwave voltage generator where each step of thevoltage corresponds to the position of the selected two of said probes.

5. The apparatus according to claim ll wherein said position indicatingvoltage generator comprises a circuit for generating a voltage thatincreases linearly corresponding to the position of the selected two ofsaid probes.

* Q 6 IO! k UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,761,807 Dated September 25, 1973 Inventor(s) Takao Kobayashi et:11.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

On the cover sheet, in t he heading, insert [30] Foreign ApplicationPriority Data: 7

p n August 5, 197 73 5911970 Japan August 25, 1970 8&038/1970 Signed andsealed this 25th day of June 197 (SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PC3-1050 (10-59) uscoMM-Dc 503764359 fi' US. GOVERNMENTPRINTING OFFICE: 199 0"366'334,

1. Apparatus for constructing a potential gradient comprising: apotential detector comprising a plurality of voltage probes havingpredetermined positions; a scanning circuit comprising switching meansconnected with each of said voltage probes and means to selectivelyswitch said switching means so as to obtain the voltage between aselected two of said voltage probes at the output of said switchingmeans; a position indicating voltage generator synchronized with saidscanning circuit so as to generate a position indicating voltagecorresponding to each of the selected two of said voltage probes at theoutput of said switching means; and X-Y construction means comprisingrecording means capable of moving in the X axis direction and the Y axisdirection in response to X axis and Y axis inputs respectively, saidoutput of said scanning circuit being coupled to one of said inputs andsaid output of said position indicating voltage generator being coupledto the other of said inputs so to record the potential gradient of thepotential distribution.
 2. The apparatus according to claim 1 whereinsaid potential detector comprises a plurality of voltage probesresiliently contacting a surface having a potential distribution andmeans for maintaining said voltage probes in predetermined positions. 3.The apparatus according to claim 1 wherein said scanning circuitcomprises fixed contacts connected with said respective voltage probesand travelling contacts successively engaging said fixed contacts. 4.The apparatus according to claim 1 wherein said position voltagegenerator comprises a stepwave voltage generator where each step of thevoltage corresponds to the position of the selected two of said probes.5. The apparatus according to claim 1 wherein said position indicatingvoltage generator comprises a circuit for generating a voltage thatincreases linearly corresponding to the position of the selected two ofsaid probes.